Sand Casting

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<p>HOME ASSIGNMENT PART II</p> <p>SAND CASTINGPrepared By-</p> <p>Sunil Sutar MTech (Design Engineering)Presented to-</p> <p>M P Gururajan Assistant Professor Applied Mechanics Department</p> <p>Different ComponentsDifferent AspectsSmall Simple</p> <p>23 feet, 6 tonnes , 99.72% iron, No rust since 5th century AD Big Complex</p> <p>Iron pillar</p> <p>Courtesy: Google images</p> <p>CastingCasting = Pattern making + Mold making + Pouring Molten Metal + Cooling + Removal + Inspection Types of Casting : Expendable Mold, Multiple Use Mold Sand Casting : Expendable Mold casting process uses sand as molding material</p> <p>Casting Terminology</p> <p>Parting line</p> <p>Courtesy: efunda</p> <p>Pattern MakingWhat is pattern? Approximate duplicate of product Pattern material: Wood, Metals, Urethanes etc. Types of Patterns: One Piece or solid pattern, Split Pattern, Match-plate pattern, Drag &amp; Cope Pattern Allowances: Shrinkage, Machining, Draft, Distortion</p> <p>Pattern Making</p> <p>One piece or Solid Pattern</p> <p>Split Pattern</p> <p>Match Plate Pattern</p> <p>Cope &amp; Drag Pattern</p> <p>Mold Making Consists : Sand Preparation and Mold Making Sand Properties : Refractoriness, Cohesiveness, Permeability, Collapsibility How to get these properties? Mold Making Methods: Hand Ramming, Sand Slinger, Jolting, Squeezing, Combination</p> <p>PouringPouring System:Pouring cup/Basin: Rectangular Shape-No vortex-No suction of Gases</p> <p>Sprue: Short-Less KE Less turbulenceTapered shapeSprue Well : Dissipate KEPrevent splashing less turbulence</p> <p>PouringRiser Need : Directional Solidification Feeding molten metal to compensate for solidification shrinkage</p> <p>Criteria: Riser should solidify after the casting.Types:</p> <p>Image Courtesy: wiki</p> <p>Cooling/SolidificationCooling Curve for a Pure Metal:Pouring Temp.: Temp of first liquid entering Mold cavity Alloy-Distinct M.P.-freezing range High Cooling Rate-fine structures-good mechanical properties Chvorinos rule : ts=B(V/A)n</p> <p>Start of Solidification</p> <p>End of Solidification</p> <p>B=Mold constant n=1.5 to 2</p> <p>Effect of Cooling rate: Process Sand Casting Permanent Mold Die Cast Cast Structure:</p> <p>SolidificationYield Strength(MPa) 55 62 110 Tensile strength(MPa) 131 158 227 Elongation(%) 8 10 9</p> <p>Image Courtesy: wiki</p> <p>Removal of Casting: Shake out-vibrating machine Shot blasting-Removal of internal surface sand</p> <p>Trimming: Excess material-manual cutting, sawingTrimming Press</p> <p>Inspection: Nobody is perfectSand Casting tooDefects</p> <p>Casting Defects:</p> <p>Image Courtesy: IITM, Manufacturing Processes, Lecture notes</p> <p>Different Sand Casting Processes:Green Sand Casting: 88% silica sand, 9% clay,3% water</p> <p>CO2 Molding: Sodium Silicate(3-6%)-CO2 flow- Strength Gain</p> <p>Shell Molding: Silica Sand + Thermo setting phenolic resin+ heat sensitive liquid catalystshot on preheated metal pattern-shell formation</p> <p>Summary:Includes :Casting=PMPCRI Sand Casting -versatile process -produce almost all size &amp; shape of components -poor surface finish and dimensional accuracy. Sand Casting Methods : Green Sand, CO2 sand , Shell</p> <p>Acknowledgements:1. Materials and Processes in Manufacturing, J T Black and Ronald A Cohser, 10 th edition. 2. Assistant Professor M P Gururajan http://mogadalai.wordpress.com/2006/01/14/somethoughts-on-making-presentations/</p> <p>Thank you</p>